1. Field of the Invention
The present invention relates to a lawn mower powered by alternative, preferably gaseous fuels, e.g., liquified petroleum gas (LPG), compressed natural gas (CNG), liquified natural gas (LNG), or other gaseous hydrocarbon fuels. The present invention uses a novel fuel injection system that includes a specially designed valve capable of regulating the flow of gas from disposable small gas canisters.
2. Description of the Related Art
Natural gas is a mixture of short-chain alkyl hydrocarbons and other gases, primarily methane, but also including ethane, propane and butane, that occurs naturally in underground chambers over petroleum deposits, and is also the lightest fraction formed when crude oil is processed. Under low temperature it condenses to form a liquid, called liquified natural gas (LNG), in which state it occupies a smaller volume than in its gaseous state, so that it may be stored and transported economically. If kept under high pressure, which also reduces its volume, but still in a gaseous state, it is called compressed natural gas (CNG). Liquified petroleum gas (LPG) is a by-product of natural gas processing and crude oil refining. Because it is composed of the heavier hydrocarbons in natural gas, primarily propane and butane, it will liquify under pressure, but reverts to a gaseous state when the pressure is released, as in an engine. Pure propane may also be used as a gaseous fuel. The same amount of energy may be provided at a lower cost by gaseous fuels than by gasoline. Gaseous fuels may also burn more cleanly, thus reducing pollution to the earth's atmosphere.
The fuel injection system uses a fuel volume arrow rod to control the volume of gaseous fuel that passes through the main body of the fuel injector housing from the fuel hose coupling to the gaseous venturi. The fuel volume arrow rod is controlled by a throttle. With the limiting valve of the present invention, small disposable gas canisters are used with the fuel injection system.
While prior art references disclose engines and machines powered by gaseous hydrocarbon fuels, none discloses a lawn mower with an engine using gaseous fuels. In addition, none of the prior art references describe the use of a fuel injection system or valve with the unique features provided by the present invention.
U.S. Pat. No. 3,978,823, issued to Michael Simon, on Sep. 7, 1976, discloses an LPG burning internal combustion engine, which is not included in or in any way connected with a lawn mower.
U.S. Pat. No. 5,203,046, issued to Patrick A. Shaw, on Apr. 20, 1993, discloses a floor buffing machine powered by propane engine, but does not teach or suggest the use of a propane or other gaseous fuel engine in a lawn mower.
U.S. Pat. No. 5,325,838, issued to David E. Bennett, on Jul. 5, 1994, discloses a liquified petroleum gas fuel injector for an internal combustion engine, but does not teach or suggest its use in a lawn mower.
U.S. Pat. No. 5,377,646, issued to Ronald E. Chasteen, on Jan. 3, 1995, discloses a gaseous fuel management system for an internal combustion engine, but does not teach or suggest its use in a lawn mower.
United Kingdom Patent Specification No. 1,158,934, published Jul. 23, 1969, discloses a method of conversion of fuel gases from the liquid to the gaseous phase.
PCT International Application No. WO 81/00282, published on Feb. 5, 1981, discloses a fuel supply system for internal combustion engines using liquified petroleum gas.
PCT International Application No. WO 92/08888, published on May 29, 1992, discloses a dual fuel injection system and a method of controlling such a system. The first fuel may be gasoline and the second fuel may be a liquified gas.
It may be seen that none of the above-mentioned prior art references teaches or suggests the use of liquified petroleum gas, compressed or liquified natural gas, or a similar fuel, or an engine powered by such a fuel, in a lawn mower. Secondly, none of the above-mentioned prior art references teaches or suggests the use of a fuel injection system or valve with the novel features and characteristics of the present invention.